The present invention relates to an electronically operated assembly to be used in conjunction with water faucets provided with sensing means that sense the presence of objects such as human hands and automatically start the flow of water. The water flow automatically stops when said object is removed from the faucet vicinity.
Automatic electrical or electronically operated faucets have been known for many years. There are a relatively large number of patents relating to such devices and systems such as U.S. Pat. Nos. 4,921,211, 4,872,485, 4,894,874 and 4,762,273; a fairly large number of other patents are cited in the above mentioned patents. These patents differ from each other by all kinds of features, such as the structure thereof or the operating method and components.
Several of the above mentioned patents are based on a passive infra-red (thermal) receiver sensitive to the temperature of a nearby object, others use ultrasonic techniques and electro-optical mechanisms incorporating Light Emitting Diodes (LED's) and Si-based detectors.
The present invention uses an electro-optical method and electro-mechanical apparatus that overcomes the deffiencies associated with prior art solution:
a) All other known methods do not afford execution of the various tasks required in dishes cleaning basins, like: filling a glass, saponification of a pot without water flow, cleaning the basin and washing hands.
b) The reflection of IR light from black objects is very weak. A conventional electro-optical proximity sensing system is thus either insensitive to black bodies or having a large dynamic range leading to susceptibility to false alarms.
c) Another problem associated with prior art electro optical automatic faucets is the fact that they are not sensitive to specular objects like a polished knife.
d) Previous methods yield a relatively high percentage of false alarms, i.e. water flow activation due to "false" objects like a nearby hand or a pile of dished in the basin.
e) Most prior art methods use network power to feed the electro-mechanical module and their design does not minimize power consumption.
f) The mechanical part and activation mechanism differes from other patents in the fact that there is no use of a solenoid to activate the valve but by an electric motor and by the mechanical transmission which need very little energy than which is required by a solenoid.
Furthermore, the opening for the release of pressure which holds the diaphragm of the main valve is achieved by a pilot valve which is not connected directly to the diaphragm. In order to obtain the pressure in the known valves a metal rod and spring is provided within the water which usually is affected by corrosion, which is not the case in the embodiment according to the invention.